The present invention relates to a window assembly and to a process for producing the assembly. More particularly, the invention contemplates a window assembly including a sheet of optically transparent material, such as glass, and a gasket of a polymeric material which is polymerized and cured in situ to encapsulate the marginal peripheral edge portion of the sheet. The gasket is typically formed by a reaction injection molding process. The assembly can be shaped to constitute a vehicle windshield, for example, in which case it can be inserted readily to close a windshield opening surrounded by a frame of appropriate shape to cooperate with the gasket of the assembly.
Initially, windshield assemblies for vehicles were comprised of a plurality of elements including adhesive sealants applied around the marginal edges of the glass sheet, suitable mechanical fasteners such as metal clips, and exterior decorative trim strips disposed to cover the junction between the marginal edges of the glass sheet and the adjacent portion of the vehicle frame.
Clearly, such structures were costly in both material and labor.
Subsequently, in an endeavor to improve the structure, unitary window assemblies of the type illustrated in U.S. Pat. No. 4,072,340 were developed. These assemblies include a sheet of glass, an adjacent frame, and a casing or gasket of molded material, such as polyvinyl chloride, extending between the frame and the peripheral edge of the window to hold the sheet of glass and the frame together. Fasteners are provided at spaced locations along the frame such that the entire assembly can be guided into location over the opening in a vehicle body as a unit with the fasteners extending through aligned apertures in the vehicle body and secured from the interior of the vehicle.
Other window assemblies, such as illustrated in U.S. Pat. No. 4,139,234, include a molded casing or gasket around the edge of the pane of glass with fasteners molded in and projecting from the casing or gasket for purposes of attachment to an associated vehicle body.
The relatively heavy frame members of the above assemblies, typically cast from zinc or other metals or alloys and/or the molded gasket or casing for securing the frame to the window provides significant weight in each window assembly. Also, as illustrated in U.S. Pat. No. 4,072,340, the exterior decorative frame, which requires fastening means along the length thereof to secure the entire assembly in a vehicle, requires expensive casing or gasket techniques rendering the frame members expensive and time-consuming to install.
In an endeavor to reduce the overall weight of a window assembly of the type discussed above and to reduce the costs thereof, other window assemblies have been developed of the general types illustrated in U.S. Pat. Nos. 3,759,004 and 4,364,595. The structure of the former patent includes a glass sheet, with a trim strip surrounding the edge thereof, secured within a suitably framed opening in a vehicle by means of an adhesive pressed between the glass and/or the trim strip and the adjacent portion of the frame around the opening of the vehicle. The trim strip is formed of flexible plastic material with a channel portion which embraces the edge of the glass sheet and a front decorative strip portion which extends from and can hinge relative to the edge of the front wall of the channel portion which lies on the inside of the trim strip when it is fitted around the glass sheet. The trim strip may be maintained in position on the glass sheet by suitable retaining clips of spring metal, for example.
The latter of the above mentioned patents illustrates another window assembly which is installed to close a vehicle opening, for example, as a unit preferably from the outside. The assembly includes a sheet of glass, one of several types of decorative frame or trim members surrounding the glass sheet, and one or more attaching members secured directly to the glass sheet but concealed from view. Preferably, the attaching means are metallic studs rigidly and securely bonded directly to the glass surface with suitable adhesive. The decorative frame member can be injection molded, the patent discloses, around the sheet of glass.
The present invention is a window assembly of comparatively low weight and cost, which can be assembled and installed in a vehicle with minimal handling costs.